Most automobiles today, and some furniture for office and home, include some movable ergonomic supports such as lumbar supports. Whether these supports move by bending or sliding, it is common for the movement to be produced by traction. A commonly used device for applying traction to movable ergonomic support parts is a traction cable, such as Bowden cable. Such cables have a sleeve or conduit having a wire inside the sleeve and disposed to slide axially through it. These cables are installed so that one sleeve end is connected to one portion of an ergonomic support and the wire end is connected to another portion. At the other end of traction cable, pulling the other wire end relative to the other sleeve end will have the effect of moving the wire end relative to the sleeve end at the ergonomic support. This movement effects the movement of the support parts.
A wide variety of actuators are used for applying the traction to the traction cable. Some are powered by electric motors. Others are manual. All of them must achieve the functional requirements that the traction cable sleeve end and the traction cable wire end be moved relative to one another, and that the actuator hold a selected position of the traction cable wire relative to the traction cable sleeve, against a return or home biased force exerted on the traction cable by the weight of the passenger on the ergonomic support. In addition to these minimal requirements, a variety of other features are valued in the market place and desirable in the actuator design. One of these is that the movement of the actuator be silent. Other continuing needs and preferences are for durability, ease of assembly, economy, a responsive and precise “feel” to the hand of the user, and a thin and compact package in order to conserve space.